386 



DISEASES OF ECONOMIC PLANTS 



most other rusts ; indeed other forms of spores are ahnost 

 entirely absent in most parts of the country, throwing the 

 burden of perpetuation of the species entirely upon the uredo 

 myceUum and its spores. This stage is known to be peren- 

 nial as far north as Washington, DC, and Lincoln, Neb. 

 The rust is very destructive, and seems to be limited to 



this one host. 



Smut. See timothy. 

 Anthracnose. See 

 rye. 



CLOVER 



Black mold {Phyl- 

 lachora Trifolii 

 (Pers.) Fckl.).— 

 Common red clover, 

 crimson clover, white 

 clover, alsike clover, 



and several other related plants are affected by this mold. 

 The chief symptoms are pale spots upon the upper sides 



of the leaves accompanied by black dots on the lower sides. 



These spots at first glance so strongly resemble the sori of 



the rusts as to lead the disease to be mistaken for a rust by 



the casual observer. 



Though the disease is often of considerable damage, no 



treatment is known. 



Sclerotiniose, wilt (Sclerotinia Trifoliorum Eriks.). — This 



wilt is possibly identical Avith the wilt of alfalfa. In any 



event it resembles it very closely. It was first noted 



in America, in Delaware, by Chester in 1889, later in New 



Jersey by Halsted. 



Fig. 1(55. — Clover leaf showing spots of black mold 

 Original. 



